Support M1 Macs using DisplayServicesGetBrightness/DisplayServicesSetBrightness

[jtbandes]

I found that these SPI functions work to get and set the brightness on my M1 MacBook Air. Fixes #34.

I have not tested this with any other system/configuration, so will need help from others to test thoroughly.

• Extracted functions from the main loop to avoid it getting too complicated.
• Also made minor changes to fix a warning about brightness being uninitialized.

[nriley]

Thanks! Testing help appreciated.

[Mike-Woolley]

Thanks @jtbandes, this change works form me on both my M1 & Intel MacBooks 😄

However one line of the PR breaks brightness -l.
Reverting that line makes everything good - I have put a comment in the commit diff to indicate where.

[Mike-Woolley]

This change breaks brightness -l.
Not sure what the purpose is?

[jtbandes]

I was trying to fix an uninitialized variable warning, but I guess I made a mistake. Thanks for catching — I’ll submit a fix soon.

[jtbandes]

@nriley, you might want to revert the if (argc > 0) usage() change as recommended by @Mike-Woolley. I think when I was reading the code I didn't realize that argc was modified.

[nriley]

Sorry, I did not mean to commit that as is. I've got a cleanup commit incoming.

[nriley]

OK, updated and tested on all the Macs I have access to. Hopefully this works for everyone else too. Thanks again for the contribution!

[new3gum2]

tested on M1 MacBook Pro 17,1.
Fails to work showing display id as 0x1 and error -536870201

[nriley]

@new3gum2 are you building from source? If so, what macOS version and are you using the internal display?

[new3gum2]

@new3gum2 are you building from source? If so, what macOS version and are you using the internal display?
Sorry I didn't have time to test further, I used the make file and it worked like charm. it is macOS Monterey
I was trying the compiled versions from brew and MacPorts neither of those worked. But the source compile worked.

[KuSi833]

@new3gum2 are you building from source? If so, what macOS version and are you using the internal display?
Sorry I didn't have time to test further, I used the make file and it worked like charm. it is macOS Monterey
I was trying the compiled versions from brew and MacPorts neither of those worked. But the source compile worked.

Can also confirm building from source works, but was getting the same error when I installed it with brew.

[mrtvocich]

Hi all, I have first tried to install brightness through Homebrew, but the app was returning an error. After compiling locally

git clone https://github.com/nriley/brightness.git      
make                                                    
sudo cp brightness /usr/local/bin/brightness   

it works great, thank you guys!